Conventional vehicular air blower incorporates a rotary electric machine to rotate a fan. The rotary electric machine has an armature including a stack-type armature core and windings wound on the armature core. The above-described armature is provided with an insulator on a surface of the armature core to insulate the armature core from the windings (refer to JP-2002-272045-A (Pgs. 4 through 6, FIG. 2) and JP-07-245896-A (Pgs. 4 through 6, FIG. 1) for example).
However, the above-described conventional insulator has the following disadvantages. FIG. 11 is an explanatory diagram showing the disadvantages of the conventional insulator, and depicts winding patterns of the winding wound on the conventional insulator in varied winding patterns.
In the respective winding patterns in FIG. 11, a reference numeral 320 denotes a conventional insulator disposed in an armature core having a plurality of radially-formed salient poles. The insulator 320 has slots 321 formed at regular intervals. Further, the slot 321 has an arc portion 322 at an inner portion in a radial direction of the insulator 320. Multi-layered windings 314 are wound in distributed winding method and disposed in the slot 321.
In a winding pattern 1, a winding 314a on a first layer is wound to be in contact with an arc portion 322 on a center axis Lc′ of the slot 321. Then, windings 314b-1, 314b-2 on a second layer are wound to be in tight contacts with inner walls 321a, 321b of the slot 321 and the winding 314a on the first layer. In this case, windings 314c, 314d of a third layer and beyond are aligned regularly.
In a winding pattern 2, the winding 314a on the first layer is wound to be in contact with the arc portion 322 on the center axis Lc′ of the slot 321. Then, the first winding 314b-1 on the second layer is wound to be in tight contacts with the inner wall 321b of the slot 321 and the winding 314a on the first layer. Further, the second winding 314b-2 is wound to be in tight contacts with the winding 314a on the first layer and the first winding 314b-1 on the second layer. In this case, the second winding 314b-2 on the second layer and the inner wall 321a of the slot 321 form a clearance C2 therebetween. However, a width of the clearance C2 is smaller than a diameter of a second winding 314c-2 on the third layer when it is deformed, so that the winding 314c-2 do not enter in the clearance C2.
In a winding pattern 4, the winding 314a on the first layer is wound to be in contact with the arc portion 322 on the center axis Lc′ of the slot 321. Then, one winding 314b on the second layer and one winding 314c on the third layer are wound. Further, a second winding 314d-2 on the fourth layer is wound to be in tight contact with the winding 314c on the third layer and the first winding 314d-1 on the fourth layer. In this case, the second winding 314d-2 on the fourth layer and the inner wall 321a of the slot 321 form a clearance C4 therebetween. However, the width of the clearance C4 is larger than a diameter of the second winding 314b-2 on the second layer in its natural state, so that the winding 314b-2 does not dig into the clearance C4.
In a winding pattern 3, the winding 314a on the first layer is wound to be in contact with the arc portion 322 at a position diverted from the center axis Lc′ of the slot 321. Then, the second winding 314c-2 on the third layer is wound to be in tight contacts with the winding 314b-1 on the second layer and the first winding 314c-1 on the third layer. In this case, the second winding 314c-2 on the third layer and the inner wall 321a of the slot 321 form a clearance C3 therebetween. The width of the clearance C3 is larger than a diameter of the second winding 314b-2 on the second layer when it is deformed, so that the winding 314b-2 may dig into the clearance C3.
In short, the armature incorporating the insulator 320 having the above-described structure has a disadvantage that the windings 314 is not regularly wound in the slot 321 if the winding 314a on the first layer is wound in contact with the arc portion 322 at a position diverted from the center axis Lc′.
Thus, if the winding 314 is not regularly wound in the slot 321, the windings 314 may dig to be damaged as described above. Especially as in the winding pattern 3, the winding 314b-2 dug in the clearance C3 is pressed radially inward by other windings wound radially outer than the winding 314b-2. Then, the winding 314b-2 is strongly pressed into the clearance C3 and an insulation of the winding 314b-2 may be spoiled.
The present invention is achieved in view of the above-described issues and has an object to provide an insulator, an armature and a rotary electric machine capable of preventing insufficient insulation of the windings.
Another object of the present invention is to provide an insulator, an armature and a rotary electric machine capable of having enough number of slots even if they are provided with a configuration capable of preventing insufficient insulation of the windings.
A still another object of the present invention is to provide a rotary electric machine capable of improving its durability relative to conventional ones.